This application discusses guides or guidewires for use in medical procedures, including flexible, kink-resistant guides or guidewires.
Elongated, flexible guidewires can be used in medical procedures to gain access to specific internal sites within the body without major surgery. Guidewires can be advanced through the body, for example, through peripheral blood vessels, the gastrointestinal tract, or the urinary tract. Guidewires can be used in, among other fields, cardiology, electrophysiology, gastroenterology, urology, and radiology.
Once positioned indwelling, the guidewire defines the path for the introduction of catheters and/or other medical instruments to a desired site; however, such instruments may be less wieldy than the guidewire, have significantly more mass, and create a risk of kinking the guidewires as they are advanced over the guidewire.
Also, hydrophilic or lubricious guidewires can be difficult to use because they may too easily migrate or slip from the desired location in a patient's body. Further, a clinician wearing plastic or latex gloves may not be able to properly grip and manipulate a hydrophilic or lubricious guidewire.
A guidewire may be constructed with a central core or core wire and a coil along the distal portion of the guidewire or surrounding the core. Generally, the dimension or size of the core essentially defines the stiffness of the guidewire along its length. For a given core material, the greater its cross-section, the greater the stiffness of the overall guidewire. The choice of core wire material affects the performance characteristics of the guidewire and affects its cost. Further, using an outer coil requires the diameter of the core wire inside the coil to be reduced or smaller to fit inside the coil and produce a guidewire with an overall outer diameter that is not too large. Stainless steel core guidewires may be inexpensive but, with reduced or small diameters, can be prone to kinking during advancement of catheters and/or other instruments thereover. Cores made of fiberglass composites may be more resistant to kinking but they can be more prone to abruptly snapping, and it is difficult to provide a taper to the distal end of the fiberglass core, to increase flexibility of the distal end, without splintering. If a guidewire is not sufficiently stiff or rigid, it may be more prone to kinking and may be more difficult to navigate and direct to a desired location in a body.
There is a need for a guidewire that maintains a relatively high degree of stiffness for better maneuverability and has beneficial outer frictional or texture characteristics.